Research Jane H Davies, Jonathan Richards, Kevin Conway, Joyce E Kenkre, Jane EA Lewis and E Mark Williams
Primary care screening for peripheral arterial disease: a cross-sectional observational study Abstract Background
Early identification of peripheral arterial disease (PAD) and subsequent instigation of risk modification strategies could minimise disease progression and reduce overall risk of cardiovascular (CV) mortality. However, the feasibility and value of primary care PAD screening is uncertain.
Aim
This study (the PIPETTE study — Peripheral arterial disease In Primary carE: Targeted screening and subsequenT managEment) aimed to determine the value of a proposed primary care PAD screening strategy. Outcomes assessed were: prevalence of PAD and agreement of ankle– brachial index (ABI)-defined PAD (ABI ≤0.9) with QRISK®2-defined high CV risk (≥20).
Design and setting
A cross-sectional observational study was undertaken in a large general practice in Merthyr Tydfil, Wales.
Method
In total, 1101 individuals with ≥2 pre-identified CV risk factors but no known CV disease or diabetes were invited to participate. Participants underwent ABI measurement and QRISK2 assessment, and completed Edinburgh Claudication Questionnaires.
Results
A total of 368 people participated in the study (participation rate: 33%). Prevalence of PAD was 3% (n = 12). The number needed to screen (NNS) to detect one new case of PAD was 31. Refining the study population to those aged ≥50 years with a smoking history reduced the NNS to 14, while still identifying 100% of PAD cases. Of participants with PAD, 33% reported severe lifestyle-limiting symptoms of intermittent claudication that warranted subsequent endovascular intervention, yet had not previously presented to their GP. The QRISK2 score predicted high CV risk in 92% of participants with PAD.
Conclusion
The low PAD yield and the fact that QRISK2 was largely comparable to the ABI in predicting high CV risk suggests that routine PAD screening may be unwarranted. Instead, strategies to improve public awareness of PAD are needed.
Keywords
cardiovascular risk assessment; general practice; peripheral arterial disease; primary health care; screening.
e103 British Journal of General Practice, February 2017
INTRODUCTION The clinical relevance of peripheral arterial disease (PAD) stems not only from its wellknown debilitating symptoms and sequelae (such as intermittent claudication, ischaemic rest pain, and limb amputation) but also from its position as a strong predictor of future cardiovascular (CV) events. PAD is a marker of systemic atherosclerosis; regardless of whether it is symptomatic or not, it has been repeatedly associated with a three- to six-fold increased risk of death from CV causes.1 Furthermore, this increased risk is independent of, and in addition to, that expected by concomitant traditional CV risk factors.2 The evidence is sufficiently robust that national and international guidelines recommend the same strategy of CV risk modification for PAD as for coronary artery disease.3–5 The disease, however, is underdiagnosed and this may be partly attributed to the fact that up to two-thirds of patients with PAD in the community are asymptomatic.4 This has resulted in calls for the instigation of primary care PAD screening via ankle–brachial index (ABI) measurement. The ABI is a measure of the ankle systolic blood pressure relative to central aortic blood pressure (approximated by measuring the brachial systolic pressure). An ABI of ≤0.9 is considered diagnostic of PAD, a cutoff point that has been shown to be >95% JH Davies, PhD, research associate and nurse, South East Wales Trials Unit (SEWTU), Centre for Trials Research, Cardiff University, Cardiff. J Richards, BSc, FRCGP, clinical director; K Conway, MD, FRCS, consultant vascular surgeon, Cwm Taf University Health Board, Merthyr Tydfil. JE Kenkre, PhD, professor of primary care; EM Williams, PhD, reader, Faculty of Life Sciences and Education, University of South Wales, Pontypridd. JEA Lewis, PhD, lecturer and research lead, School of Health Sciences, Cardiff Metropolitan University, Cardiff. Address for correspondence Jane H Davies, South East Wales Trials Unit
sensitive in detecting angiogram-positive disease and approximately 99% specific in identifying healthy subjects.6 Studies have demonstrated that an abnormal ABI (≤0.9 or >1.3) is highly prevalent among individuals not considered at high risk of CV events, as defined by CV risk scoring systems such as the Framingham Risk Score (FRS).7 According to Grøndal and Lindholt, nearly 25% of CV deaths occur in individuals believed to have low CV risk according to traditional risk stratification models;8 this has resulted in suggestions that the ABI, as a non-invasive and inexpensive test, could be added as an additional risk parameter to CV risk tools and/or algorithms.1 Current perspectives of PAD screening in the UK appear to be mixed: although UK general practices are awarded Quality and Outcomes Framework (QOF) points for having a register of patients with PAD and for meeting PAD-related targets, there is no incentive to screen patients without symptoms of the disease. Some countries (for example, the Netherlands and Australia) now offer remuneration for ABI measurement in primary care, but this is not the case in the UK. Notably, however, the UK National Screening Committee’s handbook for vascular risk assessment, risk reduction, and risk management refers to the ABI within a list of emerging novel risk (SEWTU), Centre for Trials Research, Cardiff University, Room 406, 4th Floor, Neuadd Meirionnydd, Heath Park, Cardiff, CF14 4YS, UK. E-mail: [email protected] Submitted: 20 June 2016; Editor’s response: 19 July 2016; final acceptance: 19 September 2016. ©British Journal of General Practice This is the full-length article (published online 27 Jan 2017) of an abridged version published in print. Cite this version as: Br J Gen Pract 2017; DOI: https://doi.org/10.3399/bjgp17X689137
How this fits in Routine PAD screening and subsequent appropriate treatment could minimise progression of the disease and reduce overall cardiovascular (CV) risk. This study has shown that targeting individuals aged ≥50 years who have a history of smoking could be an effective and efficient PAD screening strategy; however, results also suggest that QRISK2 could be a more amenable and comparable alternative for the identification of high CV risk in the primary care setting.
factors, but reports that there is insufficient evidence to justify its inclusion in risk assessment scores at present.9 The concept of early identification of CV risk factors and disease emerges as a pivotal theme in the UK Department of Health’s Cardiovascular Disease Outcomes Strategy, with particular reference to PAD.10 This study (the PIPETTE study — Peripheral arterial disease In Primary carE: Targeted screening and subsequenT managEment) aimed to determine the value of a proposed primary care PAD screening strategy. The outcomes assessed were: • prevalence of undiagnosed PAD/yield from screening; and
Box 1. Study inclusion and exclusion criteria Inclusion criteria • Males aged ≥45 years or females aged ≥55 years (age-related CVD risk factor); • At least one additional CVD risk factor from the following: – cigarette smoking or regular exposure to passive smoke (that is, living with a smoker); – hypertension (systolic blood pressure of ≥140 mmHg, diastolic blood pressure of ≥90 mmHg, or taking antihypertensives); – Low high-density lipoproteins (3.3 mmol/L), high triglycerides (>1.7 mmol/L), or taking lipid-lowering medication; – family history of premature coronary heart disease (first-degree male relative aged
Primary care screening for peripheral arterial disease: a cross-sectional observational study Abstract Background
Early identification of peripheral arterial disease (PAD) and subsequent instigation of risk modification strategies could minimise disease progression and reduce overall risk of cardiovascular (CV) mortality. However, the feasibility and value of primary care PAD screening is uncertain.
Aim
This study (the PIPETTE study — Peripheral arterial disease In Primary carE: Targeted screening and subsequenT managEment) aimed to determine the value of a proposed primary care PAD screening strategy. Outcomes assessed were: prevalence of PAD and agreement of ankle– brachial index (ABI)-defined PAD (ABI ≤0.9) with QRISK®2-defined high CV risk (≥20).
Design and setting
A cross-sectional observational study was undertaken in a large general practice in Merthyr Tydfil, Wales.
Method
In total, 1101 individuals with ≥2 pre-identified CV risk factors but no known CV disease or diabetes were invited to participate. Participants underwent ABI measurement and QRISK2 assessment, and completed Edinburgh Claudication Questionnaires.
Results
A total of 368 people participated in the study (participation rate: 33%). Prevalence of PAD was 3% (n = 12). The number needed to screen (NNS) to detect one new case of PAD was 31. Refining the study population to those aged ≥50 years with a smoking history reduced the NNS to 14, while still identifying 100% of PAD cases. Of participants with PAD, 33% reported severe lifestyle-limiting symptoms of intermittent claudication that warranted subsequent endovascular intervention, yet had not previously presented to their GP. The QRISK2 score predicted high CV risk in 92% of participants with PAD.
Conclusion
The low PAD yield and the fact that QRISK2 was largely comparable to the ABI in predicting high CV risk suggests that routine PAD screening may be unwarranted. Instead, strategies to improve public awareness of PAD are needed.
Keywords
cardiovascular risk assessment; general practice; peripheral arterial disease; primary health care; screening.
e103 British Journal of General Practice, February 2017
INTRODUCTION The clinical relevance of peripheral arterial disease (PAD) stems not only from its wellknown debilitating symptoms and sequelae (such as intermittent claudication, ischaemic rest pain, and limb amputation) but also from its position as a strong predictor of future cardiovascular (CV) events. PAD is a marker of systemic atherosclerosis; regardless of whether it is symptomatic or not, it has been repeatedly associated with a three- to six-fold increased risk of death from CV causes.1 Furthermore, this increased risk is independent of, and in addition to, that expected by concomitant traditional CV risk factors.2 The evidence is sufficiently robust that national and international guidelines recommend the same strategy of CV risk modification for PAD as for coronary artery disease.3–5 The disease, however, is underdiagnosed and this may be partly attributed to the fact that up to two-thirds of patients with PAD in the community are asymptomatic.4 This has resulted in calls for the instigation of primary care PAD screening via ankle–brachial index (ABI) measurement. The ABI is a measure of the ankle systolic blood pressure relative to central aortic blood pressure (approximated by measuring the brachial systolic pressure). An ABI of ≤0.9 is considered diagnostic of PAD, a cutoff point that has been shown to be >95% JH Davies, PhD, research associate and nurse, South East Wales Trials Unit (SEWTU), Centre for Trials Research, Cardiff University, Cardiff. J Richards, BSc, FRCGP, clinical director; K Conway, MD, FRCS, consultant vascular surgeon, Cwm Taf University Health Board, Merthyr Tydfil. JE Kenkre, PhD, professor of primary care; EM Williams, PhD, reader, Faculty of Life Sciences and Education, University of South Wales, Pontypridd. JEA Lewis, PhD, lecturer and research lead, School of Health Sciences, Cardiff Metropolitan University, Cardiff. Address for correspondence Jane H Davies, South East Wales Trials Unit
sensitive in detecting angiogram-positive disease and approximately 99% specific in identifying healthy subjects.6 Studies have demonstrated that an abnormal ABI (≤0.9 or >1.3) is highly prevalent among individuals not considered at high risk of CV events, as defined by CV risk scoring systems such as the Framingham Risk Score (FRS).7 According to Grøndal and Lindholt, nearly 25% of CV deaths occur in individuals believed to have low CV risk according to traditional risk stratification models;8 this has resulted in suggestions that the ABI, as a non-invasive and inexpensive test, could be added as an additional risk parameter to CV risk tools and/or algorithms.1 Current perspectives of PAD screening in the UK appear to be mixed: although UK general practices are awarded Quality and Outcomes Framework (QOF) points for having a register of patients with PAD and for meeting PAD-related targets, there is no incentive to screen patients without symptoms of the disease. Some countries (for example, the Netherlands and Australia) now offer remuneration for ABI measurement in primary care, but this is not the case in the UK. Notably, however, the UK National Screening Committee’s handbook for vascular risk assessment, risk reduction, and risk management refers to the ABI within a list of emerging novel risk (SEWTU), Centre for Trials Research, Cardiff University, Room 406, 4th Floor, Neuadd Meirionnydd, Heath Park, Cardiff, CF14 4YS, UK. E-mail: [email protected] Submitted: 20 June 2016; Editor’s response: 19 July 2016; final acceptance: 19 September 2016. ©British Journal of General Practice This is the full-length article (published online 27 Jan 2017) of an abridged version published in print. Cite this version as: Br J Gen Pract 2017; DOI: https://doi.org/10.3399/bjgp17X689137
How this fits in Routine PAD screening and subsequent appropriate treatment could minimise progression of the disease and reduce overall cardiovascular (CV) risk. This study has shown that targeting individuals aged ≥50 years who have a history of smoking could be an effective and efficient PAD screening strategy; however, results also suggest that QRISK2 could be a more amenable and comparable alternative for the identification of high CV risk in the primary care setting.
factors, but reports that there is insufficient evidence to justify its inclusion in risk assessment scores at present.9 The concept of early identification of CV risk factors and disease emerges as a pivotal theme in the UK Department of Health’s Cardiovascular Disease Outcomes Strategy, with particular reference to PAD.10 This study (the PIPETTE study — Peripheral arterial disease In Primary carE: Targeted screening and subsequenT managEment) aimed to determine the value of a proposed primary care PAD screening strategy. The outcomes assessed were: • prevalence of undiagnosed PAD/yield from screening; and
Box 1. Study inclusion and exclusion criteria Inclusion criteria • Males aged ≥45 years or females aged ≥55 years (age-related CVD risk factor); • At least one additional CVD risk factor from the following: – cigarette smoking or regular exposure to passive smoke (that is, living with a smoker); – hypertension (systolic blood pressure of ≥140 mmHg, diastolic blood pressure of ≥90 mmHg, or taking antihypertensives); – Low high-density lipoproteins (3.3 mmol/L), high triglycerides (>1.7 mmol/L), or taking lipid-lowering medication; – family history of premature coronary heart disease (first-degree male relative aged
